AS Japan honours Emperor Akihito's 61st birthday today, the nation can take pride in the knowledge that the Chrysanthemum throne is a more stabilising influence than ever.

Political leaders may appear to come and go with alarming regularity but at least the world's oldest hereditary monarchy can, in the public's view, be depended on.

After all, any institution which has remained intact for 1,400 years is unlikely to change overnight, which is more than can be said for the national leadership.

Today, four years after becoming the 125th Emperor of Japan, the figurehead of the Japanese imperial family is probably more popular than ever.

An indication of this appeal is what must qualify as an 'obsession' by Japan's media with the domestic affairs of the imperial family - particularly over prospects for a new-born member.

Hardly a day passes without some report or another surfacing in the national press about the Emperor's daughter-in-law, Crown Princess Masako, being pregnant.

The reports have all been false.

There are certainly no indications that the Crown Princess is expecting, since she embarked only last month on a Middle East visit with Crown Prince Naruhito.

They have also only been married for 18 months.

But the speculation is nevertheless telling. It is a sign of impatience.

The Japanese public, or at least the media representing the public, is anxious for the re-assurance of an heir to the throne beyond Emperor Naruhito - and a collective sigh of relief will be heard across the nation when an imminent birth is eventually announced.

Monarchies elsewhere in the world may be under various states of siege but, in Japan, the question of the Chrysanthemum throne continuing into the 21st century rarely arises.

The 1947 Constitution of Japan deprived the Emperor of all political power. His role was reduced to formal and ceremonial occasions and his obligation was to act on the advice and approval of the government.

The autonomous Imperial Household Ministry was demoted to the status of an agency of the Prime Minister's Office. A peerage system was eliminated altogether and the ruling sovereign of the day, Emperor Hirohito, himself declared on New Year's Day, 1946, that he was no longer 'divine' - or a 'heavenly sovereign' as emperors had been known since recorded history began in Japan in the 7th century.

Thus the royal family became the nation's 'first family'. Under the post-war constitution, the emperor became 'the symbol of the state and of the unity of the people, deriving his position from the will of the people with whom resides sovereign power'.

The imperial family was, from that time onwards, popularised; its duty to be united with the people in warmth and affection.

Now his subjects were citizens and the emperor was to mirror a modern, democratic Japan.

This is the situation today and one the Japanese public is generally comfortable to retain for the foreseeable future.

When Empress Michiko suffered a collapse last year in the wake of media criticism, and subsequently lost her voice for several months, the public was mortified.

When she voiced 'deep sorrow and bewilderment' at untrue gossip in the press about her becoming a domineering figure in the imperial court, the speculation was promptly dropped.

The public welcomed an announcement recently by Emperor Akihito that 'while her recovery cannot be said to be complete, I am very happy that she has overcome her speech difficulty'.

The Emperor plays his official part, too. He said royal visits to France and Spain this year were conducted 'in accordance with the decision of the government'.

Overseas, he is a goodwill ambassador and, asked about his objectives before setting off to Europe (on a tour which also took him to the United States), Emperor Akihito noted: 'I will be glad if people deepen their understanding of Japan, whose ardent wish is the peace of the world, and which is striving together with the countries of the world to contribute to the international community.' Politics, of course, is not his concern. Asked at one press conference for his opinion about nuclear weapons, the Emperor said bluntly: 'In my position, I would like to refrain from commenting on it.' Inevitably, the Japanese monarchy is sometimes compared to European models - especially since the British Royal Family is having such a tumultuous time.

Protocol obviously prevents Emperor Akihito from commenting in depth.

He would only observe recently: 'The Japanese imperial family and the royal families of Europe are rooted in the traditions of their respective countries and, while there are some differences, I think they have in common their concern for the happiness and welfare of the people and respect for democracy.'